The present invention relates to a sustained release preparation of propranolol. Specifically, it relates to an oral dosage form which provides a release period suitable for single daily dosing while exhibiting good bioavailability.
Propranolol is a well known and widely use betaadrenergic receptor blocking agent. In the oral formulations currently in use, propranolol is almost completely absorbed from the gastrointestinal tract, but it is subject to rapid liver metabolism. Administration with food has been reported to enhance its bioavailability. The biological half-life ranges from 3 to 6 hours after oral administration.
Propranolol is effective in the treatment of hypertension, cardiac arrhythmia and angina pectoris and is indicated in the prophylaxis of common migraine headaches. It is desirable to maintain a constant plasma propranolol level to compete with available beta receptor sites thereby blocking the chronotropic and inotropic responses to catecholamines. Therapeutic doses of propranolol decreases heart rate, cardiac output and blood pressure.